dc-dc scaling of 0-18V to 0-5V

[dharanikumarsrvn]

how to scale 0-18V to 0-5V without much loss..can opamp be used? else what ic can be used?

 

[ashugtiwari]

You can use linear dropout regulators, they r low cost and reliable. Yes, they r lossy and can be realized using an op-amp. Search google with keyword "op-amp regulator" and u get 100's of circuits on images click.
But if ur application is battery powered or u r concerned with power loss, then u can go for buck dc-dc switching regulators. U can make it externally but there are IC's available from linear tech and analog devices. Just key in ur required input, output voltage with max output current u need in following link:
https://www.linear.com/products/switching_regulator

Op-amps can do switching regulators as well but building everything urself make circuit go big and so the cost, these regulators are cheap and needs very few external components like shotkey diode, inductor and capacitor, with optional voltage devider.